The Invention set forth in this specification pertains to new and improved tub boxes.
More specifically it pertains to tub boxes which are related to tub boxes as are set froth in the prior Duane D. Logsdon U.S. Pat. Nos. 3,593,344 issued July 20, 1971 entitled "Tub Box Structure" and 4,742,588 issued May 10, 1988 entitled "Tub box." Both of these prior patents disclose highly utilitarian tub boxes of tub box structures which utilize a polymer or plastic lower housing section or means having a bottom and a continuous perpherial wall leading to an open top and a polymer or plastic closure or closure section or means fitting with respect to the peripherial wall so as to close off the open top in order to define an internal cavity.
In such prior structures flanges are used on the housing and closure sections to support one on the other and in order to effectively close of the interior cavity from the exterior of the assembled tub box. These flanges are formed so that effectiveness of the seal between them is primarily dependent upon how well they fit against one another. While in many cases this is satisfactory there are cases where warpage of the plastic has warped for one reason or another or where a contaminant such as some dirt has gotten between the flanges. In such cases the internal cavities in these prior structures are not considered to have been adequately been closed off, This is believed to have been particularly the case since these structures have not used effective means to hold or secure the flanges together.
Such prior structures are considered to be somewhat less that fully or completely desirable for another, additional reason. This concerns the problem of locating them so that a drain pipe extends into their interiors. Because of the time and the complications involved in cutting a hole in a wall for a pipe to enter through a bottom or perpherial wall of a housing section of a tub box the more recent of the two patents noted in the preceding recognized the importance of forming the housing section of a tub box so as to include knockout pipe openings which could be opened up in a wall by a simple physical blow or the easy use of a cutting tool.
Unfortunately neither of the indicated patents recognized that in many cases it would be difficult or undesirable to fit a tub box housing section over the end of a pipe or in fitting a pipe through such a hole in assembling the tub box and the pipe together so that the tub box could be used. It is considered that his had the effect of limiting the use of prior tub boxes as noted.